Apparatus and method for monitoring and controlling heating and/or cooling systems

• US 4,903,759 A
• Filed: 09/25/1987
• Issued: 02/27/1990
• Est. Priority Date: 09/25/1987
• Status: Expired due to Fees

• Current Assignee: John G. Lapeyrouse
• Original Assignee: John G. Lapeyrouse
• Inventors: Lapeyrouse, John G.
• Primary Examiner(s): BENNETT, HENRY A
• Application Number:
  US07/101,176
• Time in Patent Office: 886 Days
• Field of Search: 236/10, 236/11, 236/46 R, 236/91 F, 165/11.1
• US Class Current: 165/11.1
• CPC Class Codes: F24F 11/30 for purposes related to the operation of the system, e.g. for safety or monitoring
• CPC Class Codes: F24F 11/46 Improving electric energy efficiency or saving
• CPC Class Codes: F24F 11/526 giving audible indications
• CPC Class Codes: F24F 11/61 using timers
• CPC Class Codes: F24F 11/63 Electronic processing
• CPC Class Codes: F24F 11/88 Electrical aspects, e.g. circuits
• CPC Class Codes: F24F 2110/10 Temperature
• CPC Class Codes: F24F 2110/12 of the outside air
• CPC Class Codes: G05D 23/1917 using digital means
• CPC Class Codes: Y10S 165/002 Energy, efficiency, performance or malfunction

Abstract

This invention relates to an apparatus and method for monitoring and controlling a heating and/or cooling system which controls the temperature of air in a conditioned space within a building and to such an apparatus and method capable of indicating the performance of such a system and effectuating control over the system for maximizing the operating efficiency of the system. As compared with a conventional control system, additional temperature sensors are provided to sense the temperatures of air drawn into and discharged from a temperature modifying unit such as an air handling unit having a heat exchange coil. The sensed temperatures are then used as a basis for determining the differential attained by flowing air through the unit, and compared with a desired differential taken as indicating an optimal condition, with the percentage of attainment of the optimal differential being visually displayed for an operator of the system. The attainment or non-attainment of certain target differentials within certain predetermined time intervals is used to control the operation of the system by either stopping such operation and draw attention to a clearly defective system or cycling the system to operate a satisfactory system in the most economical way. Application to systems other than circulating air systems is suggested.

Claims

1. In an apparatus for changing the temperature of air in a conditioned space and having a first temperature sensor for sensing the temperature of air in the conditioned space and a temperature modifying unit for circulating a flow of air through the conditioned space and changing the temperature of the flowing air, the unit being operatively connected with and responsive to the first temperature sensor, an improved system for monitoring the efficiency of operation of the apparatus and comprising:

second and third temperature sensors for sensing the temperature of circulating fluids;

said second temperature sensor sensing the temperature of a supply fluid circulated to said temperature modifying unit;

said third temperature sensor sensing the temperature of a return fluid circulated from said temperature modifying unit;

processor means operatively connected with and responsive to said temperature sensors for comparing the temperatures sensed by said second and third temperature sensors and determining the temperature differential therebetween and the percentage of a predetermined optimum differential between the sensed return air and supply air temperatures which has been attained and generating a percentage signal representative of such percentage; and

annunciator means operatively connected with said processor means and responsive to the generation of a percentage signal for displaying a visual indication of such percentage.

2. Apparatus according to claim 1 wherein said annunciator means comprises analog display means for indicating the percentage of attainment of said optimum differential.

3. Apparatus according to claim 2 wherein said analog display means indicates the percentage of attainment in the manner of a bar graph.

4. Apparatus according to claim 1 wherein said annunciator means comprises digital display means for indicating the percentage of attainment of said optimum differential by a numerical display.

5. Apparatus according to one of claims 1, 2 or 3 wherein said second temperature sensor senses the temperature of return air drawn to the unit and said third temperature sensor senses the temperature of supply air expelled from the unit.

6. Apparatus according to claim 5 further comprising means for sensing the flow of air through the unit and for generating a signal indicative of such flow being within a predetermined satisfactory range, and further wherein said processor means is operatively connected with and responsive to said air flow sensing means for varying the generation of a percentage signal in the event that such flow drops below said predetermined satisfactory range.

7. In an apparatus for changing the temperature of air in a conditioned space and having a first temperature sensor for sensing the temperature of air in the conditioned space and a temperature modifying unit for circulating a flow of air through the conditioned space and changing the temperature of the flowing air, the unit being operatively connected with and responsive to the first temperature sensor, an improved control system for optimizing the efficiency of operation of the apparatus and comprising:

second and third temperature sensors for sensing the temperatures of return air drawn to the unit and supply air expelled from the unit;

a timer operatively connected for timing intervals of operation of the unit;

processor means operatively connected with and responsive to said temperature sensors and said timer for determining whether a predetermined percentage of a predetermined optimum differential between the sensed return air and supply air temperatures has been attained within a predetermined time interval and functioning for interrupting operation of said unit in the event of a determination that said predetermined percentage of said optimum differential has not been attained within said predetermined time interval.

8. Apparatus according to claim 7 wherein said processor means further determines whether said optimum differential has been attained within a second predetermined time interval and functions for generating an error signal in the event of a determination that said optimum differential has not been attained within said second predetermined time interval and further wherein said annunciator means is operatively connected with said processor means and responsive to the generation of an error signal for displaying a warning that the apparatus is operating below a desired efficiency.

10. Apparatus according to one of claims 7 or 9 wherein said processor means determines whether said optimum differential has been attained before a desired temperature has been attained in the conditioned space and functions for cycling said unit on and off in the event of a determination that said desired temperature has not been attained in the conditioned space upon said optimum differential being attained.

9. In an apparatus for changing the temperature of air in a conditioned space and having a first temperature sensor for sensing the temperature of air in the conditioned space and a temperature modifying unit for circulating a flow of air through the conditioned space and changing the temperature of the flowing air, the unit being operatively connected with and responsive to the first temperature sensor, an improved control system for optimizing the efficiency of operation of the apparatus and comprising:

second and third temperature sensors for sensing the temperatures of return air drawn to the unit and supply air expelled from the unit;

a timer operatively connected for timing intervals of operation of the unit;

processor means operatively connected with and responsive to said temperature sensors and said timer for determining whether a predetermined optimum differential between the sensed return air and supply air temperatures has been attained within a predetermined time interval and functioning for generating an error signal in the event of a determination that said optimum differential has not been attained within said second predetermined time interval; and

annunciator means operatively connected with said processor means and responsive to the generation of an error signal for displaying a warning that the apparatus is operating below a desired efficiency.

11. In an apparatus for changing the temperature of air in a conditioned space and having a first temperature sensor for sensing the temperature of air in the conditioned space and a temperature modifying unit for circulating a flow of air through the conditioned space and changing the temperature of the flowing air, the unit being operatively connected with and responsive to the first temperature sensor, an improved control system for optimizing the efficiency of operation of the apparatus and comprising:

second and third temperature sensors for sensing the temperatures of return air drawn to the unit and supply air expelled from the unit;

a timer operatively connected for timing intervals of operation of the unit;

processor means operatively connected with and responsive to said temperature sensors and said timer for determining whether a predetermined optimum differential between the sensed return air and supply air temperatures has been attained before a desired temperature has been attained in the conditioned space and functioning for cycling said unit on and off in the event of a determination that said desired temperature has not been attained in the conditioned space upon said optimum differential being attained.

12. In an apparatus for changing the temperature of air in a conditioned space and having a first temperature sensor for sensing the temperature of air in the conditioned space and a temperature modifying unit for circulating a flow of air through the conditioned space and changing the temperature of the flowing air, the unit being operatively connected with and responsive to the first temperature sensor, an improved control system for optimizing the efficiency of operation of the apparatus and comprising:

second and third temperature sensors for sensing the temperatures of return air drawn to the unit and supply air expelled from the unit;

a timer operatively connected for timing intervals of operation of the unit;

processor means operatively connected with and responsive to said temperature sensors and said timer for determining (a) whether a predetermined percentage of a predetermined optimum differential between the sensed return air and supply air temperatures has been attained within a first predetermined time interval and (b) whether said optimum differential has been attained within a second predetermined time interval and (c) whether said optimum differential has been attained before a desired temperature has been attained in the conditioned space, said processor means functioning for (d) interrupting operation of said unit in the event of a determination that said predetermined percentage of said optimum differential has not been attained within said first predetermined time interval and (e) generating an error signal in the event of a determination that said optimum differential has not been attained within said second predetermined time interval and (f) cycling said unit on and off in the event of a determination that said desired temperature has not been attained in the conditioned space upon said optimum differential being attained; and

annunciator means operatively connected with said processor means and responsive to the generation of an error signal for displaying a warning that the apparatus is operating below a desired efficiency.

13. In an apparatus for changing the temperature of air in a conditioned space and having first temperature sensing means in the conditioned space for sensing the temperature of air in that space and an air handling unit with a fan for circulating a flow of air through the conditioned space and a temperature modifying element for changing the temperature of air flowing through the air handling unit and operatively connected with and responsive to the first temperature sensing means, an improved control system for optimizing the efficiency of operation of the apparatus and comprising:

second and third temperature sensing means for sensing the temperatures of return air drawn to the air handling unit and supply air expelled from the unit;

timer means for timing intervals of operation of the temperature modifying element;

processor means operatively connected with and responsive to said temperature sensing means and said timer means for determining the differential between the return and supply air temperatures and for comparing the determined differential over time with a predetermined optimum differential, said processor means being operatively connected with the temperature modifying element for interrupting operation thereof and generating a warning signal in the event that the determined differential is below a predetermined percentage of the optimum differential after a predetermined time interval;

annunciator means operatively connected with said processor means and responsive thereto for warning an operator in the event that the determined differential is below the optimum differential after a second, longer predetermined time interval; and

cycle means operatively connected with said processor means and responsive thereto for cycling the temperature modifying element off and on in the event that the determined differential equals the optimum differential at a time that the first temperature sensing means senses that the temperature in the conditioned space is other than a predetermined desired temperature.

14. In a method of controlling the temperature of air circulating in a conditioned space and which includes steps of sensing the temperature of air in the conditioned space, circulating a flow of air through the conditioned space and changing the temperature of the flowing air in response to any difference between the sensed temperature thereof and a desired temperature, an improvement in monitoring the efficiency of the method which comprises the steps of sensing the temperatures of return air drawn from the space and supply air returned to the space;

responding to the sensed return and supply temperatures by comparing the return and supply temperatures and determining the temperature differential therebetween and the percentage of a predetermined optimum differential between the sensed return air and supply air temperatures which has been attained;

generating a percentage signal representative of such percentage; and

responding to the generation of a percentage signal by displaying a visual indication of such percentage.

15. A method according to claim 14 wherein the step of displaying a visual indication of a percentage comprises displaying a numerical indication of such percentage.

16. A method according to claim 14 wherein the step of displaying a visual indication of a percentage comprises displaying an analog representation of such percentage.

17. In a method of controlling the temperature of air circulating in a conditioned space and which includes steps of sensing the temperature of air in the conditioned space, circulating a flow of air through the conditioned space and changing the temperature of the flowing air in response to any difference between the sensed temperature thereof and a desired temperature, an improvement in monitoring the efficiency of the method and controlling the temperature change which comprises the steps of sensing the temperatures of return air drawn from the space and supply air returned to the space;

responding to the sensed return and supply temperatures by comparing the return and supply temperatures and determining the temperature differential therebetween and the percentage of a predetermined optimum differential between the sensed return air and supply air temperatures which has been attained;

determining whether a predetermined percentage of the predetermined optimum differential between the sensed return air and supply air temperatures has been attained within a predetermined time interval;

interrupting operation of said unit in the event of a determination that said predetermined percentage of said optimum differential has not been attained within said predetermined time interval; and

generating an alarm signal for alerting an operator to an equipment shutdown.

18. A method according to claim 17 further comprising the steps of determining whether said optimum differential has been attained within a second predetermined time interval;

generating an error signal in the event of a determination that said optimum differential has not been attained within said second predetermined time interval; and

responding to the generation of an error signal by displaying a warning that the apparatus is operating below a desired efficiency.